With development in IT in recent years, lithium ion secondary cells are used as power sources for almost all mobile instruments such as portable telephones, notebook-size personal computers, and digital camera. However, with an improvement in the performances of these mobile instruments, the power consumption thereof tends to become increasingly large. Attention has been paid to fuel cells, which are clean and high in efficiency, for power sources or for charging the instruments.
As such a small-sized and light fuel cell, known is a fuel cell as described in, e.g., Patent Document 1 described below, which has a solid polymer electrolyte in a plate form, an anode side electrode plate arranged on one of both sides thereof, a cathode side electrode plate arranged on the other side, an anode side metallic plate arranged on the outside of the anode side electrode plate, and a cathode side metallic plate arranged on the outside of the cathode side electrode plate, wherein the outer circumferential regions of these metallic plates are fastened onto each other to interpose an insulating member therebetween, thereby sealing the fuel cell. However, the sealing based on the fastening of the metallic plates results in problems that the process becomes complicated and precision is required for controlling the thickness of the fastened region.
Thus, in order to make the sealing step simple, Patent Document 2 described below suggests a fuel cell having a solid polymer electrolyte in a plate form, and electrode plates and metallic plates that are equivalent to those of the above-mentioned fuel cell, wherein a sealing material such as epoxy resin is used to seal only circumferential edge regions of both of the metallic plates while an insulating member is interposed therebetween.
Patent Document 3 described below suggests a cell member for a fuel cell, which has a solid polymer electrolyte in a plate form, and electrode plates (each composed of a catalyst layer plus an electroconductive porous body) each arranged on both sides of the electrolyte, wherein the circumferences of the individual layers are integrated with each other through an insert-molded resin frame. In this invention, electroconductive members (a connecting member 18 and others) for leading out electricity to the outside are arranged outside the resin, and contact the electroconductive porous bodies at small areas. The electroconductive members are not covered with the resin.